From d44de14e1928e7e5c3fc55843de7d3a024f07af5 Mon Sep 17 00:00:00 2001
From: Olly Dutton <ollydutton@gmail.com>
Date: Thu, 2 Oct 2025 09:13:16 +1000
Subject: [PATCH] fix(checkbox): Support optional boolean type

---
 src/field/schema.ts |  2 +-
 test/fields.test.ts | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/field/schema.ts b/src/field/schema.ts
index 60c394d3..e2686831 100644
--- a/src/field/schema.ts
+++ b/src/field/schema.ts
@@ -15,7 +15,7 @@ function addCheckboxAttributes(inputType: string, field: Field, schema: NonBoole
   field.checkboxValue = schema.const
 
   // However, if the schema type is boolean, we should set the valid value as `true`
-  if (schema.type === 'boolean') {
+  if (Array.isArray(schema.type) ? schema.type.includes('boolean') : schema.type === 'boolean') {
     field.checkboxValue = true
   }
 }
diff --git a/test/fields.test.ts b/test/fields.test.ts
index d39165d3..35f1d914 100644
--- a/test/fields.test.ts
+++ b/test/fields.test.ts
@@ -686,6 +686,18 @@ describe('fields', () => {
       expect(field?.checkboxValue).toBe(true)
     })
 
+    it('uses checkbox input for boolean/null type array with boolean const value', () => {
+      const booleanNullSchema = {
+        'x-jsf-presentation': {
+          inputType: 'checkbox' as const,
+        },
+        'type': ['boolean', 'null'],
+      }
+      const field = buildFieldSchema(booleanNullSchema, 'test')
+      expect(field?.inputType).toBe('checkbox')
+      expect(field?.checkboxValue).toBe(true)
+    })
+
     // Skipping these tests until we have group-array support
     describe('array type inputs', () => {
       it('uses group-array when items has properties', () => {